バイオセンサ法による乳カゼイン分解物中のペプチドの測定

概要

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A biosensor sensing peptides was developed for the monitoring of the hydrolytic degree of milk casein. Leucine aminopeptidase and L-amino acid oxidase were co-immobilized onto an acetylcellulose membrane with an asymmetric structure. The biosensor which consists of the co-immobilized enzymes and a H_2O_2-sensing polarographic electrode responded to both peptides and L-amino acids, but not to high molecular weight proteins such as bovine serum albumin and milk casein. This peptide sensor generated 4.8 pA electric current per 1 μM of L-leucylglycylglycine at 37℃, pH 7.0 in 50 mM phosphate buffer solution, and was stable for more than 3 months. The peptide sensor can measure the combined concentration of L-amino acids and peptides produced by the cleavage of casein using L-leucylglycylglycine as a reference. When milk casein is hydrolyzed with a free protease in a bioreactor, the amount of total peptides increased logarithmically against the % hydrolysis of casein measured by a conventional method. It increased linearly with an immobilized protease on chitosan beads. The accessibilities of the protease to its cleavage sites may account for the observed differences in the pattern of casein hydrolysis. This biosensor is expected to be a powerful tool for the monitoring of the hydrolytic degree of proteins in a bioreactor in the food and fermentation industry.
社団法人日本生物工学会の論文
1989-11-25